High-Yield Synthesis of Colloidal Carbon Rings and Their Applications in Self-Standing Electrodes of Li-O2 Batteries

J Am Chem Soc. 2023 Dec 20;145(50):27664-27671. doi: 10.1021/jacs.3c09716. Epub 2023 Dec 1.

Abstract

The use of carbon materials in porous electrodes has impressive advantages. However, precisely tailoring the multilevel pore structure of carbon electrodes remains an unsolved challenge. Here, we report a highly efficient site-selective growth strategy to synthesize colloidal carbon rings by templating patchy droplets. Carbon rings are used for the direct fabrication of self-standing porous electrodes with hierarchical pores for lithium-oxygen batteries (LOBs). In situ atomic force microscopy reveals that during discharge the discharge products densely nucleate and grow on carbon rings, demonstrating that such rings are a very potential electrode material in LOBs. The hollow carbon ring electrode (HCRE) possesses micrometer-scale channels formed by random packing of rings and nanochannels consisting of ring-shaped hollow cavities connected by nanosized pores in the wall. Both channels contribute to ion transportation and gas diffusion, but the storage of the discharge products mainly lies in micrometer-scale channels, leading to a high discharge capacity of LOBs (20 658 mAh/g). Our work paves a new way to construct hierarchically porous electrodes for application in electrocatalysis and electrochemical energy storage.